Ecophysiological strategies to daily air temperature variations in two key species in the northwestern slope of the superpáramo of the Antisana volcano
Authors
Jaramillo Terán, Ricardo Mauricio
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Date
2016
Journal Title
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Volume Title
Publisher
PUCE - Quito
Abstract
Background: Tropical alpine plants experience daily freezing risk, yet little is known about the
interaction between their surroundings and thermal traits. Existent studies are based on
information taken over short periods of time, which does not allow to understand the effects of
inter-annual climate variations on plants.
Aims: To evaluate if Werneria nubigena and Xenophyllum rigidum present similar response
mechanisms to freezing, determine if their inner leaf temperature (ILT) is controlled by
microhabitat conditions, and if the exotherm temperature variation depends on the
correspondent response to freezing.
Methods: We measured the ILT and the micro environmental temperature, and evaluated the
exotherm and freezing injury temperature (LT50), on the Antisana Volcano.
Results: The thermal niche of both species was warmer than the registered ILT. The exotherm
and LT50 relation revealed that both species presented a tolerance mechanism to freezing with
an inversed relation with elevation. Microhabitat substrates (rock and vascular plants)
surrounding the plants determined the exposure to freezing for both species, having a significant
inverse relation with the ILT.
Conclusions: Our results indicate that independently of their tolerance mechanism,
microhabitat conditions could be the primary filter when determining the exposure of these
tropical alpine species to air freezing temperatures.
Description
Keywords
Tropical alpine plants, Temperature variations, Freezing tolerance, Andes Ecuador - Antisana